diff --git a/configure/os/CONFIG.win32-x86.Common b/configure/os/CONFIG.win32-x86.Common
index c76af8ea3..8ea906688 100644
--- a/configure/os/CONFIG.win32-x86.Common
+++ b/configure/os/CONFIG.win32-x86.Common
@@ -26,6 +26,3 @@ endif
 
 # Needed to find dlls for base installed build tools (antelope,eflex,...)
 PATH := $(EPICS_BASE_BIN):$(PATH)
-
-# Silence the tr1 namespace deprecation warnings
-USR_CXXFLAGS_WIN32 += -D_SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING
diff --git a/configure/os/CONFIG.win32-x86.win32-x86 b/configure/os/CONFIG.win32-x86.win32-x86
index 22ce15967..a8115a714 100644
--- a/configure/os/CONFIG.win32-x86.win32-x86
+++ b/configure/os/CONFIG.win32-x86.win32-x86
@@ -107,6 +107,9 @@ CODE_CPPFLAGS += -D_CRT_SECURE_NO_DEPRECATE -D_CRT_NONSTDC_NO_DEPRECATE
 WARN_CXXFLAGS_YES = -W3 -w44355 -w44344 -w44251
 WARN_CXXFLAGS_NO  = -W1
 
+# Silence tr1 namespace deprecation warnings
+WARN_CXXFLAGS += -D_SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING
+
 #
 # -Ox maximum optimizations
 # -GL whole program optimization